The selection of retarder is one of the most critical factors in the design of high temperature cement slurry system.In order to reasonably select and apply the retarder,AMPS-IA copolymer retarder was used to react with Dalian G-grade oil well cement.The thickening performance of cement,the material composition and microstructure characteristics of hydration and hardening products were tested by high temperature and high pressure thickener,X-ray diffractometer,scanning electron microscope and energy spectrometer,and its applicability was analyzed.The results showed that AMPS retarders as high-temperature retarders had good retarding effect,good thickening line shape and long thickening time.However,in the process of repeated experiments to evaluate the stability of retarder,there was a certain probability that retarder failed,and the thickening curve fluctuated,resulting in abnormal gelation of cement slurry.Gelation was caused by the chelating-adsorption effect of retarder polymer molecules on cations,which caused a large number of polymer molecules to aggregate outside the gel.
AMPSRetarderOil well cementThickening timeAbnormal gelation
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